If your website works with a www but not without one, your e-mails are not getting delivered or your website is not available at all… chances are you have a DNS problem…
What is DNS anyway?
DNS stands for Domain name system. Each domain name such as mywebsite.com has a ‘Zone File’ which contains a range of records pertaining to that domain. It has a record that says where your website is, a record that says what do do with e-mails and a whole load of other useful records which keep everything relating to a domain name working.
A simple way to think of DNS is it’s like a helpful local. The local knows where the pub, post office and gym are. When asked the local will point whoever is asking for directions in the right direction to get to where they want to go. Of course if that local gets knocked on the head by a stray cricket ball and suffers some temporary amnesia, he wont be very helpful at pointing people in the right direction! People either get lost and never find the place they were looking for, or it takes them a lot longer to find the place then it would have had they have been given accurate directions.
MXToolbox
MXToolbox is one of my favourite tools. The name is a little misleading though, MX records are a type of record in a DNS Zone file that relate to e-mail. So on first glance you would think MXToolbox just checks MX records. However it actually looks up the whole range of records. One of the most useful features on the site is the ‘Domain Health’ page where you put in a domain name and a Pass/Warning/Error traffic light system highlights any issues found and a description of the problems discovered. All completely free to use.
There is also a subscription service you can sign up to that monitors your domains and notifies you if any problems appear. There are three tiers and the first tier is absolutely free, but has substantially less features then the two paid tiers.
intoDNS
IntoDNS is very simple to use. Unlike MXToolbox where there are various different tools and checks you can run, IntoDNS is just one test. Displaying the various DNS records, and highlighting any potential issues.
Final Thoughts
DNS issues can be scary when you come across them. Sometimes warnings are only warnings and may not be issues at all. So try not to freak out, if you can still see your website in a browser chances are the issues are not as serious as it may seem.
Finally, DNS changes are slow. DNS changes can take 72 hours (if not more) to take effect, so when it comes to DNS there is no such thing as an instant fix. Sometimes in trying to fix something you may actually break it, but not know for a few days until the changes take effect. This is why you should get an expert to look into any DNS issues you come across, and why it is important to check DNS regularly using the tools mentioned after making any changes.